1. Technical Field of the Invention
This invention relates to a vertical type of double disc surface grinding machine, in which a pair of grinding wheels opposing each other in vertical direction are installed, a work is securely clamped to a work clamping jig provided on a rotary table, the work is supplied to a grinding position located between the grinding wheels, and both upper and lower surfaces of the work are ground simultaneously while the work is rotated around a spindle axis of the work clamping jig.
2. Prior Art
Generally, the vertical type of double disc surface grinding machine is equipped with a work supplying device suitable for a supplied work according to its size and type. In a work which can not be held at its center and is small in its rigidity such as a piston ring etc., for example, a work supplying device is used wherein the work is held in a work holding hole formed on a thin-plate type rotary carrier in such a way that both upper and lower end faces of the work are protruding from the hole respectively, and the work is supplied to the grinding position between the grinding wheels while making the work spin itself by means of a ring gear mechanism etc. Further, even when the work has a high rigidity such as a connecting rod or its shape is complicated not like a rotation body, the work supplying device is used wherein the rotary carrier including the above-mentioned work holding hole is provided in order to hold the work in a freely rotatable manner.
On the other hand, for a work which is a rotation body as like an automobile disc brake and has a constant rigidity so as not to be deformed even when held at its central portion, a work supplying device is used wherein a central portion of the work is clamped to a clamping jig and the work is rotated together with the rotating spindle of the clamping jig so that the work is supplied to the grinding position between the grinding wheels.
In general, the both upper and lower grinding wheels of the vertical type of double disc surface grinding machine are so designed as to be movable in vertical direction. The upper grinding wheel is equipped with an adjusting mechanism for adjusting an inclination angle of its spindle axis, so that the wheel can be adjusted in its parallelism with respect to the lower grinding wheel. A spindle axis of the lower grinding wheel has been fixed to its vertical position when shipped.